| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kennewick | 1 | 89,136 | 84,015 | 0.87% | 3,127 | 29 | City |
| Richland | 2 | 66,182 | 60,892 | 1.42% | 1,558 | 42 | City |
| West Richland | 3 | 19,879 | 16,364 | 3.23% | 899 | 22 | City |
| Prosser | 4 | 6,756 | 6,139 | 1.53% | 1,307 | 5 | City |
| Benton City | 5 | 4,116 | 3,487 | 2.41% | 1,654 | 2 | City |
Kennewick is the largest city in Benton County, with a population of 89,136.
Benton City is the smallest city in Benton County, with a population of 4,116.
There are 5 cities in Benton County, Washington.